Lua协程调度器：大任务切片到每帧

-- 错误：一帧内建完百控件，白屏两秒像卡死
function buildAll()
    for i = 1, 100 do
        buildWidget(i)
    end
    showMain()
end

local tasks = {}
local function addTask(body)
    tasks[#tasks + 1] = coroutine.wrap(body)
end
local function onFrame()
    for i = #tasks, 1, -1 do
        local ok = pcall(tasks[i])
        if not ok then
            table.remove(tasks, i)
        end
    end
end